Published 4:00 am, Wednesday, October 29, 2003

2003-10-29 04:00:00 PDT Washington -- Justice Department and FBI officials have imposed tighter secrecy restrictions over the inquiry into the leak of the identity of a CIA operative,

government officials said Tuesday. In an unusual step, they have removed the director of the FBI's Washington office from the list of officials with access to the case.

The official, Michael A. Mason, one of the FBI's most senior managers, was taken off the list in an effort to restrict information about the case, the officials said.

Customarily, a senior official like Mason would have full access to details of the case, which is being investigated mainly by agents from his office, although it is being supervised by FBI headquarters. One bureau official said Mason had asked to be removed, although others said the decision was based on whether the officials had a need to know.

Investigators are trying to determine whether it was White House officials or others who told columnist Robert Novak that Valerie Plame, wife of a former ambassador, Joseph C. Wilson IV, was an employee of the CIA, as Novak wrote in his syndicated column in July. Wilson has been critical of the administration's Iraq policies.

At a news conference on Tuesday, President Bush was asked why he had not directed White House staff members to sign affidavits saying that they were not behind the leak.

"The best group of people to do that so that you believe the answer is the professionals at the Justice Department," Bush said.

Democrats have said that Attorney General John Ashcroft's relationship with the White House creates a conflict of interest and that he should recuse himself or appoint a special counsel to lead the inquiry.

The decision to drop Mason and other officials from the list was made after Ashcroft stressed to subordinates the importance of avoiding leaks in the case, one of the most politically delicate investigations of his tenure.

Mason is a highly regarded agent who recently took over the prestigious Washington job after heading the bureau's office in Sacramento. Several officials said his removal from the list was an effort to tighten security around the case and was not intended as a slight to him.

Some investigators have said the FBI is making steady progress in determining who disclosed the information to Novak, following a paper trail of meetings of Bush administration officials in which Wilson was discussed.